Intra-articular Ganglion Cyst from Medial Collateral Ligament of the Knee Joint: A Case Report and Review of the Literature

A 57-year-old male complained of a painful sensation on the medial joint line of the right knee for about 5 years. A palpable soft mass measuring about 5.5 × 4.0 × 2.0 cm was found on the medial joint line. Plain roentgenography showed bulging soft tissue over the medial aspect of the right knee. Sonography revealed a hypoechoic intra-articular soft tissue mass. Magnetic resonance imaging revealed a multilobulated homogeneous cystic lesion originating from the medial collateral ligament, with hypointensity on T1-weighted images and hyperintensity on T2-weighted images. We performed an arthroscopic examination before surgical excision of the tumor to rule out a parameniscal cyst, and no meniscal tear was found. Microscopic examination proved that the excised tumor was a ganglion cyst. The patient was free of his previous symptoms and had no recurrence at 2-year follow-up